Nidagravel gravel stabilisation grids are the original honeycomb gravel stabilisation system for paths, driveways, and car parks.

Here on our 'Frequently Asked Questions' page, we have tried to provide detailed and useful answers to many of the questions we are regularly asked by our customers. We have included topics that cover most applications such as gravel paths, driveways, and car parks and you will find answers to questions about gravel sizes and types of gravel, our gravel grids, and wheelchair access, dealing with manholes covers, laying honeycomb grids over concrete and tarmac surfaces, permeability and drainage, installing gravel grids, sloping driveways and more. We will be regularly updating this page in the future to add more answers to gravel grid installation questions as well as useful tips and general information on using Nidagravel gravel stabilisers and Nidagreen artificial grass underlay.

Our gravel stabilisation system or gravel grids along with the Nidagravel brand name and trademark was developed over 25 years ago by Nidaplast in France, who specialise in the manufacture of honeycomb plastics for a wide range of applications and industries, in fact, Nidaplast pioneered the development of plastic honeycomb products for a wide range of applications including gravel stabilisation back in the 1980s. The unique Nidagravel honeycomb cell system was developed specifically for the stabilisation of gravel and designed to be lightweight with high compressive strength and offer long-term durability. Designed to invisibly hold gravel in place, the honeycomb cell system is completely hidden from view, ensuring that all you see is a perfect gravel surface is that completely stable, 100% permeable, and easy to use with minimal gravel movement or migration. Nidagravel is extremely versatile, lightweight, and easy to install and maintain - it really does make the difference! Nidagravel grids are the best way to create a hard-wearing and beautiful gravel driveway, gravel car park, gravel path or seating area. Nidagravel gravel stabilisation grids are used extensively for private gardens and commercial projects across the UK by professional installers and DIYers alike. Our gravel grids, which are sometimes referred to as gravel mats, geocells, drive grids and gravel trays are used by building, landscaping, and civil engineering contractors across the UK. If you are looking for a professional contractor to install a new gravel driveway or refurbish an existing one, please visit our Contractor Link to search for a contractor in your area.

Nidagravel UK - Making gravel surfaces perform better...

Yes. Nidagravel 129, 130 & 140 gravel stabilisation grids all have a membrane attached to the underside of the grid or sheet. The membrane is thermally bonded to the bottom of the honeycomb cells in production using a hot glue process and extends on two sides (1 long side and 1 short side) so that it forms an overlap. When installing Nidagravel grids the overlaps of the membrane are laid flat and the adjoining gravel grids are then laid on top of the overlap when butting sheets together during installation. This ensures continuity of the membrane across all joints.

Why is it important that your gravel grids have a membrane?

Having a membrane attached to the underside our gravel grids is important for a number of reasons as follows:

1. The membrane prevents gravel from moving underneath the grids and ensure the gravel stays in the individual cells.
2. The membrane adds extra stability to both the gravel grids themselves and the installation.
3. The membrane helps inhibit weed growth.
Partly. Nidagravel does not prevent weed growth completely, but it does inhibit weed growth, which is slightly different. Unfortunately, there is no way to completely prevent some wind blown seeds from germinating in a gravel surface, that's just nature. But Nidagravel does inhibit and help reduce weed growth in the following ways:

  • The membrane on the underside of Nidagravel gravel grids helps prevent any weed growth emerging from the sub-base or sub-grade. There should not really be any weed growth growing from under the sub-base. When installing a sub-base it is best practice to lay a heavy duty, porous membrane underneath.
  • The membrane on the underside of Nidagravel gravel girds also helps to deter deep-rooted perennial weeds from penetrating the sub-base and becoming fully established.
  • Any weeds that do manage to establish themselves should have a small root structure. The growth of any weed roots are restricted to an individual cell. The weeds cannot penetrate the plastic side walls of the cell and the membrane beneath inhibits the roots penetrating the sub-base. As Nidagravel grids are 100% water permeable, during hot dry periods in the summer, many weeds will soon suffer from a lack of water and eventually dry out and die.
  • Any weed that does appear through wind blown seed or bird droppings is unable to anchor in the gravel within the Nidagravel honeycomb and can easily be removed.

  • A Nidagravel gravel grid surface, whether its a gravel garden path, a gravel driveway or a gravel car park, should be maintained in the same way as any outdoor space. When it comes to weeds, these can either be removed simply by hand or sprayed off with a suitable chemical weed killer.
    This depends on which of our gravel grids you choose. We recommend the following gravel sizes for use with our gravel stabilisation grid range:

    Nidagravel 129 Gravel Grids
    Maximum gravel size approx 10 - 12mm
    Minimum gravel size approx 6mm
    If using a mixed size gravel then a gravel type with a size range of 4 - 14mm is acceptable to use.

    Nidagravel 130 Gravel Grids
    Maximum gravel size approx 10 - 12mm
    Minimum gravel size approx 6mm
    If using a mixed size gravel then a gravel type with a size range of 4 - 14mm is acceptable to use.

    Nidagravel 140 Gravel Grids
    Maximum gravel size approx 20mm
    Minimum gravel size approx 6mm
    If using a mixed size gravel then a gravel type with a size range of 4 - 20mm is acceptable to use.

    We recommend the above gravel sizes, as these sizes of gravel fill the individual cells of the Nidagravel grids nicely and allows the gravel to compact well within each cell with minimal voids spaces. This ensures the cell walls are supported gives Nidagravel a very high compressive strength. Using this size of gravel also means that Nidagravel grids are 100% permeable and free draining across the total area of the installation.

    Whatever gravel you choose, we recommend that you use an angular gravel, chipping or decorative aggregate. Angular gravels will naturally interlock well and when angular gravels are used in combination with Nidagravel grids, this makes for an extremely stable and strong surface.
    When installing any of our gravel stabilisation grids for paths and driveways, it is not uncommon to find manhole covers of varying shapes and sizes located where you are installing your gravel grids. One of the most common places to find a manhole cover on your property is on the driveway as drains often exit a property down the driveway where they join up to the main sewerage system. Depending on the age of the property the design and construction of the manhole or inspection chamber will vary along with the size, shape, and type of manhole cover that sits on top. The only way to find out what type of manhole you have is to lift the lid and take a look. Older properties may have a brick-built manhole and a cast iron manhole frame and cover sitting on top. Modern and newly build properties will usually have a plastic circular inspection chamber with a base unit at the bottom and a number of riser sections fitted on top which lead up to the finished ground level and the inspection or manhole cover. Manholes can vary in depth from 400mm to 1m deep or more. Once you have identified the type of manhole you have you can decide how you want to deal with the manhole cover. We will cover the steps required to adjust your manhole cover in the sections below.

    Changing Levels - New gravel driveway
    You may be changing the levels slightly when installing a new gravel driveway or refurbishing an existing driveway, which means you may have to adjust the height of your manhole chamber before you can change the manhole cover. This might sound like a daunting task, but it is in fact not that difficult to do and a competent DIYer should be able to complete this.

    Changing Levels - Refurbishing a concrete or tarmac driveway
    Where customers are refurbishing their existing concrete or tarmac driveway with Nidagravel grids to create a gravel driveway surface then manhole covers are usually raised slightly so that they finish flush with the Nidagravel surface that sits on top of the concrete or tarmac. Nidagravel grids are the only way to effectively stabilise gravel on a concrete or tarmac surface. The thickness of our gravel retention system when installed varies slightly depending on the grid used, but manholes are usually raised by 50 to 70mm or in accordance with new site levels where adjustments have been made.

    Choosing and changing your manhole cover
    Manhole covers come in various shapes, sizes, and colours as we have mentioned before, which means there are plenty of options available when it comes to changing your manhole cover. It is important to remember that a manhole cover is there to allow you to inspect your drains and to allow access for drainage rods that are used to unblock a drain, so the frame and cover need to be installed properly and allow access. When it comes to choosing your manhole cover your first decision to make is - do you want to see a manhole cover or would you prefer to make it blend in with the driveway surface. If you are happy to see the manhole cover, then if your existing manhole cover is in good condition - simply re-use it. It's the quickest and simplest option and you know it will fit onto your chamber. If your manhole cover is old or damaged, you can replace it like for like. If you are doing this you should measure the frame and cover or better still take them will you to your local builder's merchants and find a suitable replacement. You may have a circular, square, or rectangular cover in place.

    Adjusting brick-built inspection chambers with cast iron frames and covers
    Older properties will probably have a brick-built inspection chamber and the underground pipework is probably salt-glazed pipework, rather than plastic pipework which is used today. Original manhole covers are often made of cast iron and are pretty heavy. You can still purchase cast iron manhole frames and covers today, so there is no problem replacing an old damaged one. Replacing a manhole cover and adjusting the height of the inspection chamber does not interfere with your drains, it is usually a small adjustment to suit the new finished surface level. To reduce the height of a brick-built manhole, you simply need to remove the cover and knock off the frame with a lump hammer and chisel. Then you can knock off one, two, or three courses of bricks to take you down to the required level, taking into account the thickness of your new manhole cover. It is a good idea to put a plastic sheet or similar inside the chamber while removing bricks so that any debris is caught and can be removed (obviously, remove this when you are finished, do not leave it in the drain). You do not want half a brick falling into your drain as it will cause a blockage. It's also a good idea to request that no-one uses and flushes the loo whilst you are working on the manhole chamber or you might get a nasty fright! Once you have reduced your brickwork, simply mortar the new frame and tray into position at the correct level. Point everything up neatly inside and out and you're done.

    If the manhole cover is too low. Then it is simply a case of adding extra layers of brickwork to bring the chamber up to the required level and fitting the new manhole frame and cover. Again take precautions to prevent debris from falling into the drains.

    Adjsting circular plastic inspection chambers with plastic frames and covers
    Modern inspection chambers are often made of plastic. Usually, there is a base section, where the pipe entries are, and then a number of connecting risers that are added on top of the base and lead up to the finished height with a frame and cover on top. The principle of reducing the chamber is the same as a brick chamber, but instead of knocking off courses of brickwork, you will cut down the plastic riser with a saw. The simplest way to do this is 'in situ'. So if you need to reduce the height of the chamber by 150mm, for example, you can dig out around the manhole riser giving yourself approx 30cm clearance all around and to a depth of about 200mm. This will give you access to saw the riser down whilst keeping it in position. There are often lines in the plastic that you can follow to ensure you make a level cut. You may find the manhole has not actually been set level or the riser section has moved a bit over time. When making your cut, you can factor this in and make a correction so that top of the riser becomes level. Then you can simply backfill, compact, and mortar your new frame and tray into position. This technique will work well for medium to deep chambers. If you are working with a particularly shallow chamber then you may have to take a slightly different approach to achieve the same result.

    To increase the height of the chamber, you will need to buy a new riser of the correct diameter that will fit onto the risers below. The risers are normally sold in standard heights. So, you may still need to cut the new riser down a bit to finish at the required height when fitted. To fit the new riser, again it is best to dig out around the top of the chamber a bit and clean off the top of the riser you are adding to. Make sure there is no grit or mud left on the rim, so that you get a nice snug fit when you put the new riser on top. Again backfill and compact as required and mortar the new frame and tray into position.
    We recommend the use of angular gravel to fill our gravel grids because the angular shape naturally interlocks together well and when combined with our gravel grids this gives the most stable gravel surface. Angular shaped gravels or decorative aggregates are not a special type of gravel. Most types of gravel available to buy in the UK are angular in shape and include gravel types like golden flint, black basalt chippings, granite chippings, limestone, and Cotswold chippings, etc. These types of gravel are widely available from sand and gravel suppliers, builders merchants, and online suppliers across the UK and there is a huge range to choose from with colours varying from white gravel to black and various shades of buff, brown, and grey gravels inbetween.

    Round pebbles are best avoided. Scottish pebbles are a good example of a gravel that is not ideal to use with your gravel grids as they are very smooth and rounded and do not interlock together well.

    If you are unsure if the gravel you have chosen is suitable to use with your Nidagravel gravel stabilisation grids please do not hesitate to contact us for advice. Please send us an email with your gravel details.
    Yes, Nidagravel gravel stabilisation grids are suitable for wheelchairs. Nidagravel grids form a stable and firm gravel surface that is suitable for wheelchair users, mobility scooters, and other users with a disability. Nidagravel grids have been used both in the UK and Europe for a wide range of projects where access for disabled users in wheelchairs is a requirement.

    Under the current government building regulations which cover 'Access to and use of Buildings'. There is a section referred to as 'Approved Document M' which ensures that people are able to access and use buildings and their facilities. Set out within this document are a large number of building regulations that cover all aspects of the design of a building, taking into account disabled users. This document covers everything from ramp gradients and path widths to handrail heights and flush thresholds. It also provides some notes on external surfaces for wheelchair users, although the details of what makes a suitable external ground surface for a wheelchair user are, to be honest, a bit vague. The following are some notes regarding external ground surfaces for wheelchair access taken from the current version of the 'Approved Document M':

    1. Document reference - 3.45 Private Outdoor Space (Part F, Page 50)
    All paved areas have a suitable ground surface

    2. Document reference - Appendix A: Key Terms - Suitable Ground Surface Note (Page 53)
    The external ground surface is firm, even, and smooth enough to be wheeled over, is not covered with loose-laid materials such as gravel and shingle, and has a maximum cross fall of 1:40

    So not a great deal to go on, but Nidagravel gravel stabilisation grids do satisfy the criteria require within the 'Approved Document M' as follows:

    1. Nidagravel grids do create a firm, even surface that is smooth enough to be wheeled over.
    2. Nidagravel grids contain gravel within a system of honeycomb cells. The surface is not loose gravel or shingle.
    3. Nidagravel grids do not require a cross fall for drainage like paving slabs as they are 100% permeable. They can be laid on a perfectly flat and level surface.
    4. Nidagravel grids are also referred to as 'Porous Paving' and also fall under the category of paving when dealing with external surfaces.

    So, there is no issue using Nidagravel gravel stabilisation grids for projects such as pathways, driveways, and entrances that are going to be used by wheelchair users. It is more a case of using a common-sense approach to the design of the space and dealing with site levels that are the two most important factors in ensuring the project is as suitable as it possibly can be for wheelchair users. Ensuring that there is plenty of space and room for a wheelchair user to maneuver comfortably and wherever possible creating level areas and shallow, gradual slopes and ramps are key to a successful project that is easy for a wheelchair user to access.

    Click the link below to download and view the full 'Approved Document M'
    Building Regulations - Approved Document M
    We recommend that customers use Nidagravel 140 gravel grids for gravel up to 20mm in size. Nidagravel 140 gravel grids are 2m long x 1.2m wide and 40mm thick. The extra depth of the Nidagravel 140 grids can accommodate the use of decorative gravels up to 20mm in size. We recommend that 20mm gravel is the maximum size gravel that can be used with Nidagravel 140. Any gravel larger than this size is not suitable for use with Nidagravel 140 and should not be used.

    You can also use smaller gravels, chippings and decorative aggregates with Nidagravel 140 gravel grids. The smallest single size gravel we would recommend using is 6mm. So there is a wide choice of decorative gravels available to choose from.
    Nidagravel 129, 130, and 140 gravel stabilisation grids are designed specifically for stabilising gravel. They are also designed to be lightweight and to have a high compressive strength when filled with gravel. Nidagravel 129, 130, and 140 gravel grids work by holding loose gravel within lots of small honeycomb cells. These honeycomb or hexagonal cells prevent the gravel in each cell from moving. On the underside of each gravel grid, there is a geotextile membrane, which is thermally bonded to the bottom of the grid. This prevents any gravel from moving underneath the grids and inhibits weed growth.

    When installing Nidagravel and filling the grids with gravel, the grids are overfilled by 20 - 25mm. The gravel that is within the cells cannot move and forms a very stable and coarse surface. The overfill gravels interlocks with the gravel held within the cells and this ensures there is very low movement of the surface layer of gravel.

    When filled with gravel our Nidagravel 129, 130, and 140 grids have a very high compressive strength. Nidagravel 129 and 130 have a compressive strength of 300 tonnes per sqm and Nidagravel 140 has a compressive strength in excess of 400 tonnes per sqm. Any loads imposed on the surface are transferred through both the gravel and the grid to the sub-base below which provides the foundation for the Nidagravel layer above.

    Benefits of using Nidagravel
    Find out more about the benefits of using the Nidagravel gravel grid system
    No, we do not deliver any orders this way. All orders are despatched via our external hauliers and the standard vehicle used for delivery is an 18 - 20 tonne curtain side HGV equipped with a heavy-duty tail lift. Delivery is to the kerbside, as in most cases, the delivery vehicle is too large and too heavy to access residential properties. The vehicle will stop at the kerbside to make delivery. The driver will unload your order (which will be on a standard or jumbo pallet or pallets, depending on the product and quantity ordered) using a manual pallet truck. The pallet will be lowered to the ground using the tail lift and the driver will move the pallet to a suitable location at the front of your property.

    How we deliver:
    Click here to find out more about how we deliver
    We hold a large stock of our Nidagravel gravel stabilisation grid range, which means our gravel grids are always in stock and we aim to deliver your order within 48 hours from placing your order (this excludes bank holidays and weekends). Once you have successfully placed your order online, you will receive two emails from us. We will email you an order confirmation and copy of your invoice along with a confirmation of successful payment from SagePay. Once your order has been processed by the sales team we will email you a confirmation of delivery date.

    How we deliver:
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    Yes, you can. We supply small samples of our Nidagravel 129, 130, 140, and IG040 gravel grids and our Nidagrass IG040 grass grids for customers to have a closer look at our gravel and grass stabilisation products, prior to making a purchase. Our samples are approx. 20cm x 20cm and boxed individually. If you are unfamiliar with Nidagravel grids or gravel and grass stabilisation grids in general, it can be handy to order a sample. Nidagravel 129, 130 and 140 gravel stabilisers have been specifically designed to stabilise gravel. They are also designed to be lightweight with a high compressive strength when filled with gravel and to be invisible when installed. Please note that Nidagravel 129, 130 and 140 are not suitable for soil or grass stabilisation. For heavy-duty and commercial gravel stabilisation projects Nidgravel IG040 is ideal and for grass reinforcement projects us Nidagrass IG040.

    Click here to order a sample of Nidagravel 129
    Click here to order a sample of Nidagravel 130
    Click here to order a sample of Nidagravel 140
    Click here to order a sample of Nidagravel IG040
    Click here to order a sample of Nidagrass IG040
    In order for Nidagravel gravel stabilisation grids to offer the best possible surface for wheelchair users it is important that our gravel grids are combined with the right size and type of decorative aggregate. We recommend using 10 - 12mm angular gravel or chippings to provide a flat and firm surface for wheelchair access. This size and type of gravel can be useful with Nidagravel 129, 130 and 140 gravel grids.

    We recommend using a 10 - 12mm gravel because this size of gravel lays nice and flat and is easier to push a wheelchair over than larger sized gravels. We also recommend using an angular gravel or chipping. Whilst we always recommend using angular gravels, whatever the application, it is more important where wheelchairs are concerned, as this creates the most stable surface possible when combined with our grids. Hard limestone, quartz and granite chippings are particularly suitable as they naturally interlock well.
    The smallest size gravel or decorative aggregate that we recommend for use with Nidagravel 129, 130 and 140 gravel grids is 6mm, if you are using gravel that has been graded to a particular size. If you are using gravel which contains a range of sizes, for example, gravel that is advertised as being 4mm - 10mm in size. This would also be suitable for use with our full range of gravel grids.
    All orders are despatched on an 'all-day window' between approx. 9.00am and 5.00pm. You can contact us on the morning of delivery for an ETA (Estimated time of Arrival) and we will obtain an ETA for you from our hauliers. You can request an ETA by phone or email.

    How we deliver:
    Click here to find out more about how we deliver
    Yes, you can. There is no option to select a delivery date when placing an order online via our website. All orders received via our website will automatically be delivered within 48 hours. But if you require delivery on a specific date, simply place your order online and then send us a separate email with the date you would like delivery along with your contact details and order number. We will ensure that your order is despatched for delivery on the date requested. But please note that delivery dates are NOT GUARANTEED as we use an external haulage company and problems with delivery can occur that are outside of our control.

    How we deliver:
    Click here to find out more about how we deliver
    Yes, you can. In fact, you can probably park several. When Nidagravel grids are filled with gravel they achieve their full compressive strength. Our gravel stabilisation grids are specifically designed for stabilising gravel. Nidagravel grids are also designed to be lightweight with a very high compressive strength when filled with gravel. All our gravel grids have multi-purpose uses and they can all be used for driveways, the choice of gravel grid for your project will mainly depend on three things, the area of the driveway, the size of gravel being used, and the slope gradient of the driveway. Our range of honeycomb gravel grids, Nidagravel 129, 130, and 140 are normally used for residential driveways. Our heavy-duty commercial gravel grid Nidagravel IG040 is not normally needed for a domestic driveway, but in some circumstances, it can be the appropriate grid to use. For technical advice or to discuss a project please contact us.

    Nidagravel 129 Gravel Grids
    Compressive Strength, when filled with gravel, is in excess of 300 tonnes per sqm
    Suitable for driveways with an area up to 50 SQM (approx.)
    Link to Nidagravel 129

    Nidagravel 130 Gravel Grids
    Compressive Strength, when filled with gravel, is in excess of 300 tonnes per sqm
    Suitable for driveways with an area over 50 SQM
    Link to Nidagravel 130

    Nidagravel 140 Gravel Grids
    Compressive Strength, when filled with gravel, is in excess of 400 tonnes per sqm
    Suitable for driveways over 50 SQM. Heavier use driveways and steeper sloping driveways.
    Link Nidagravel 140

    Nidagravel IG040 Gravel Grids
    Compressive Strength, when filled with gravel, is in excess of 800 tonnes per sqm
    Suitable for heavy-duty commercial driveway and car parks.
    Link Nidagravel IG040

    View our gravel stabilisation grid driveway projects
    Nidagravel Case Studies

    The compressive strength tests have been undertaken by the manufacturer Nidaplast using an ISO844 test method. Nidagravel gravel stabilisation grids are made by Nidaplast in France and they specialise in manufacturing honeycomb plastic products for a wide range of applications and industries. In fact, Nidaplast is considered a world leader in the production of honeycomb plastics, so you can be assured of the quality and durability of our gravel grids.
    Yes you can. Nidagravel gravel grids can be laid directly against house brickwork without causing any problems to the house brickwork or foundations. Nidagravel grids are 100% permeable and allow rainwater to pass directly through the honeycomb sheets, which will then percolate away through the sub-base and sub-grade. It is important to note that any finished external surfaces that surround a house our building should not breach the DPC (Damp Proof Course) and building regulations currently recommend that finished external surfaces be 150mm below the DPC, which is approximately 2 courses of metric brickwork
    You cannot fill Nidagravel 129, 130, and 140 gravel stabilisation grids will soil as they are specifically designed for stabilising gravel surfaces, whether that's a gravel garden path, a gravel driveway or gravel car park. These gravel grids are not designed to be filled with soil.

    We have a grass reinforcement grid that is designed to be filled with soil and seeded with grass seed to create grass driveways and parking areas. Nidagrass IG040 grass grids are green in colour to blend in with the grass and are made from 100% recycled plastic. For more information on our grass grids and to order online click the link Nidagrass
    No, you do not need to peg down Nidagravel gravel grids and we, therefore, do not supply any pegs or similar products. Pegging down, clipping together, or using any other form of fixing clip is simply not required when installing Nidagravel gravel stabilisation grids. Nidagravel grids are laid out over a prepared sub-base with each sheet butted together. On large projects, we recommend that our gravel grids are laid in rows with a staggered joint. A bit like laying bricks in the standard stretcher bond pattern. This is not absolutely essential, but it is good practice as it offsets the joints between sheets. Once our gravel grids are installed as per our installation guidelines and filled with gravel - the weight of the gravel is more than sufficient to hold the grids in place, even on slopes of up to 15%.

  • The weight of gravel holding down a single sheet of Nidagravel 130 is approx. 168 - 180 kg (per sheet)
  • The weight of gravel holding down a single sheet of Nidagravel 140 is approx. 192 - 204 kg (per sheet)
  • No pegging down is required. Nidagravel grids can be laid on slopes up to 15% or 8.53 degrees and do not require pegging down
  • No clipping sheets together. Little plastic clips are not required and do not offer additional strength benefits
  • No. Specialist tools are not required to lay, cut or fill Nidagravel grids. Our gravel stabilisation grids are simple to install and any competent DIYer can install our grids following our installation guidelines. A selection of standard tools are all that is required as follows:

    Tools required for laying Nidagravel grids
    None required. Both our small grids (Nidagravel 129) and our large grids (Nidagravel 130 and Nidagravel 140) are lightweight and easy to handle. One person can simply pick up a gravel grid and lay one at a time. When laying our grids, you will notice two overlaps of the geotextile membrane on one long side and one short side of the grid. Make sure the long overlap is facing you, which should mean the short overlap is on the right-hand side. This allows you to fold out the overlaps and lay them flat against the sub-base. You can then lay your next sheet against the sheet you have already laid. Laying it on top of the overlap of membrane. This ensures the membrane runs under all the joints. Nidagravel grids do not require pinning in place and do not require any fixing clips. The sheets are butted up to each other and when filled, the weight of the gravel it more than sufficient to hold the grids in place.

    Tools required for cutting Nidagravel grids
    The simplest way to cut Nidagravel grids is with a small angle grinder. Any size angle grinder is fine to use and a standard masonry or diamond grit cutting disc is suitable. An angler grinder will cut quickly and cleanly straight through the grid and membrane. When installing your Nidagravel grids in rows, when you get to the end of a run, you will inevitable have to cut the grid to fit. You can cut Nidagravel to any shape and cutting grids to follow a curved edge is really easy to do. When cutting Nidagravel to fit, we recommend that the piece to be cut is measured accurately. There is some tolerance or leaway when cutting Nidagravel grids and a gap of 10 - 20mm is acceptable. The grids should not be forced into position or pinched as they need to sit flat against the sub-base. When the grids are filled with gravel, you can also fill in any small gaps around the perimeter of the installation.

    Tools required for filling Nidagravel grids
    To fill your Nidagravel grids, a shovel, wheelbarrow and rake are all that is required. Once you have laid your gravel grids it is important not to move any heavy loads onto them, as they do not achieve their full loading bearing strength until filled with gravel. The best way to fill Nidagravel grids with gravel is to start in one corner or along one edge and fill this section with gravel. Using the back of a rake, rake out the gravel to fill the cells, making sure that you over fill the cells by 20 - 25mm as you go. Then working off the section of Nidagravel you have just filled you can continue to fill the grids with gravel until you have covered the full area.

    The principles above also apply to installing large areas of Nidagravel.
    Yes, you can. All Nidagravel gravel stabilisation grids are lightweight and easy for one person to lift, move, and install. Just be careful on a windy day with Nidagravel 130 and 140 as each sheet is 2.4 sqm in size (2m long x 1.2m wide) and they can be caught by the wind when moving them around. On windy days it's a lot easier for a two-man team to install Nidagravel 130 and 140 grids. Due to the smaller size of Nidagravel 129 grids, the wind is not a problem when moving them around and their lightweight compact size makes them ideal for small to medium DIY projects.

    If you are planning on installing a large Nidagravel driveway, you will probably require the services of a landscaping or building contractor to complete the installation due to the quantity of materials and groundworks involved in the project.
    Nidagravel is specifically designed for stabilising gravel surfaces and to be light in weight with a very high compressive strength when filled with gravel. Nidagravel grids vary in weight depending on the product as follows:

    Nidagravel 129 Gravel Grids
    Weight 1.25 kg per grid
    Weight 1.3 kg per sqm

    Nidagravel 130 Gravel Grids
    Weight 3.24 kg per grid
    Weight 1.35 kg per sqm

    Nidagravel 140 Gravel Grids
    Weight 4.32 kg per grid
    Weight 1.8 kg per sqm

    For more details please read the product descriptions for each Nidagravel gravel stabilisation grid. You can also download a technical data sheet for each of our gravel grids, which provides full technical information.
    Nidagravel 129, 130 and 140 gravel stabilisation grids are all very easy to cut to size on site. Two methods are commonly used to cut Nidagravel gravel grids. The simplest way to cut Nidagravel grids to shape is with an angle grinder. Most landscaping and building contractors opt to cut sheets using petrol saws or electric angle grinders, as this gives a nice clean cut and is quick to complete. A diamond grit or masonry disc can be used and these discs will cut easily through the polypropylene honeycomb sheets and the geotextile membrane on the underside.

    Alternatively if you are a DIYer, then a handsaw can be used, which is still a pretty quick way quick to cut through Nidagravel grids. We recommend using a fine tooth saw with 9 or 10 TPI (teeth per inch) rather than a course saw blade, which can snag on the honeycomb cells. When cutting gravel grids with a handsaw, you will need to measure and mark the piece to be cut first and then place this on something suitable for cutting.

    Nidagravel gravel stabilisation grids are simple to cut to fit any shape, size or angle. Whether that's a straight cut, an acute angle or long sweeping curves. This makes Nidagravel a very versatile option for stabilising your gravel surface no matter how complicated the layout or design. Nidagravel grids are frequently used for paths, driveways, and car parks, but have also been used to stabilise gravel in some elaborate garden designs including formal gardens, a maze and some intricate swirling patterns.
    Nidagravel 129, 130 and 140 gravel stabilisation grids are white in colour. In the UK we only supply this range of Nidagravel grids in white. This is basically the colour of the plastic material used to manufacture Nidagravel grids. The geotextile membrane which is bonded to the underside of Nidagravel 129, 130 and 140 in production is also white.

    Nidagravel is designed to be an invisible gravel stabiliser and when filling our gravel grids with decorative gravel, the grids should be filled to the top and then overfilled by 20 - 25mm. This overfill depth of gravel allows for some natural settlement and compaction of the gravel after installation as the loose gravel settles down and compacts into the individual cells. The gravel overfill hides the grids so all you see is a perfect gravel surface. You should not see the Nidagravel grids after installation, which makes our gravel grids suitable to use with any colour of decorative aggregate.
    Yes, you can. Nidagravel gravel grids are the ideal way to stabilise gravel that is to be laid directly over concrete, tarmac and block paved driveways. In fact, a gravel grid is the only way you can install gravel successfully over a solid slab. It is also probably one of the most cost effective ways to refurbish an existing concrete driveway. Using Nidagravel grids as an overlay to an existing concrete driveway means that you will save on the time, noise, mess and cost of breaking out and removing a large expanse of concrete, which in many cases will need to be replaced with a new sub-base.

    When we talk about installing Nidagravel grids, we often talk about a sub-base and compacting it properly. The reason for installing a sub-base is to create a firm, level, stable foundation onto which the surfacing layer can be installed. If you already have a concrete, tarmac or block paved driveway then this is already a firm, stable foundation and Nidagravel grids can be laid on top. When installing Nidagravel grids over a concrete driveway there are a number of points to take into consideration to ensure that you can complete a successful installation, as follows:

    Is the concrete base structurally sound?
    Your concrete or tarmac base needs to be structurally sound, as you don't want it to start crumbling or subsiding. If your concrete slab has been in situ for years and has previously been used as a driveway, then it's likely to be thick enough and any settlement of the surface will most likely have already happened. There may be settlement cracks in the surface of the concrete, but this is not necessarily a problem if the slab has already settled. If you have any concerns about the stability of your concrete slab, you can seek professional advice from a contractor. You can also cut out a section of the slab to check how thick it is and to see what it is laid on. Once you are happy that your concrete slab is sound, you may need to repair the slab as required to ensure you have a flat surface to work off. This may be as simple as screeding over a sunken area with a strong mortar mix to level up the concrete slab.

    Are there any drainage issues with the existing concrete driveway?
    As Nidagravel grids are 100% permeable, any rainwater falling on the surface will gradually pass through the gravel grids and make its way along the concrete slab below following any existing falls until it reaches an existing drainage point. The drainage characteristics of the concrete slab will therefore remain the same. If there are any issues with drainage, such as pooling water, etc these will need to be addressed before you install Nidagravel gravel stabilisation grids.

    What are the levels of any DPC's of any buildings adjacent to the installation?
    When installing Nidagravel grids over an existing concrete driveway, you will of course, be raising the finished surface level slightly. It is therefore important that you do not breach any DPC's (Damp Proof Courses). On new properties, you will usually find the DPC is two courses of brickwork or approx 150mm above finished exterior surfaces. On older properties, the DPC may be in a different position.

    Nidagravel 129 Gravel Grids
    This gravel grid 29mm thick
    Plus depth of overfill gravel of approx 20mm
    Total thickness when installed is approx 50mm (on top of concrete slab)

    Nidagravel 130 Gravel Grids
    This gravel grid 30mm thick
    Plus depth of overfill gravel of approx 20mm
    Total thickness when installed is approx 50mm (on top of concrete slab)

    Nidagravel 140 Gravel Grids
    This gravel grid 40mm thick
    Plus depth of overfill gravel of approx 20mm
    Total thickness when installed is approx 60mm (on top of concrete slab)

    How to deal with level changes at the entrance to the driveway or garage
    As the finished surface level will be increased by 50 - 60mm dependant of which gravel grids you plan to install. You may need to adjust the driveway entrance so that the Nidagravel grids sit flush behind a kerb or threshold of block paving or stone setts. You may also need to adjust the levels at the entrance to a garage, as the garage door may not open / close due the increase in height of the surface. There may not be an issue with either of these things, but it is a common issue to overcome when laying Nidagravel grids over an concrete surface. Depending on your project there may be a number of solutions, but one solution is to cut the slab back by approx 1.5m at the driveway and garage entrance. The concrete should be broken out and removed. It can then be replaced with sub-base material, which can be graded and compacted to finish flush with the concrete slab and taper down so that it finishes 50 - 60mm lower than the kerb at your driveway entrance or garage floor. The Nidagravel grids can then be installed in the normal way on top of these graded sections and this will ensure that the finished gravel surface is completely flush and at the same level as the original concrete slab. This will ensure that you can drive smoothly onto the gravel grids when entering your driveway and also when driving into your garage.
    Nidagravel gravel stabilisation grids are 100% permeable. The full surface area of a Nidagravel gravel path, driveway or car park will be permeable. Any rainwater that falls on to the Nidagravel grid surface will immediately drain through the stabilised gravel surface and percolate (filter gradually through a porous surface) through the sub-base and sub-grade.
    Ideally yes, but this can be optional, subject to the application, and is ultimately up to the customer. Where gravel surfaces are stabilised with Nidagravel grids it is certainly a good idea to use some sort of edging to separate your gravel surface from your lawns or borders. Where your Nidagravel grid surface finishes against a boundary wall, house wall, paved or hard surface, it may not be necessary to install an additional edging in these locations. Whatever edging option you decide to install, it must be fit for purpose and robust enough for its intended usage, so that the edging functions correctly over the lifetime of the installation. Below are some edging options that can be used with Nidagravel gravel grids:

    Pathway Edgings
    Pathways that are only going to have foot traffic can be edged with almost any type of edging material. These include timber edging, metal edging, bricks, stone setts, block pavers, and decorative edgings such as scalloped of victorian edgings. Installation of these types of edgings vary, but they can be pegged into place or concreted into position subject to the type of material being used.

    Driveway Edgings
    Edgings to driveways must be robust enough for the intended application and installed correctly so that they can withstand being driven over accidentally. We would recommend that all driveway edgings are concreted into position and backed up with a mortar haunch, as required. Thin timber edgings are not really suitable to use for a driveway edging. Treated landscape sleepers, oak sleepers, or reclaimed railway sleepers can be used as driveway edgings as these are sufficiently large pieces of timber for external use. Timber sleepers should still be concreted into position when installed as a driveway edging. Metal edgings can be suitable for driveway edgings provided that the metal edging itself is sufficiently thick and strong enough. Some types of metal edgings are pinned into position, but it is also recommended that when used for driveways, that metal edgings are also concreted into position. Stone and masonry edgings are often suitable to use as driveway edgings and include granite setts, block pavers, concrete kerbs, engineering bricks, clay paviors, and natural stone edgings, etc. This type of edging is usually concreted into position and jointed, as required. Depending on the type and size of the edgings being used, they can either be installed flush (at the same level) with the gravel surface, or in the case of an attractive, decorative edging they can be partially visible so that the edging design can be seen.

    The two main reasons to install robust driveway edgings and concrete them into position is firstly to ensure that the edging material itself is strong enough to take the weight of a vehicle without being damaged. Secondly, when driveway edgings are concreted into position, the concrete bedding and haunch, not only ensure the edgings are fixed securely, but it also supports the perimeter edge of the sub-base and prevents any lateral movement or subsidence of this part of the sub-base when the weight of a vehicle is imposed on the very edge of the driveway.

    Driveway Entrances
    The entrance to a driveway may need be to treated slightly differently to the edgings that are installed to the perimeter of the driveway. It is important that, at the entrance to the driveway, Nidagravel grids are laid flush with the driveway entrance levels, so that any vehicles entering the driveway can drive onto the gravel grids smoothly. This ensures that the gravel grids cannot move laterally and that the leading edge of the gravel girds are protected behind the driveway entrance edgings. It is both good practice and makes for an attractive driveway entrance, to lay a band or threshold of block paving, stone paviors, or setts across the entrance to a driveway. When laying a stone sett or black paver threshold to a driveway entrance, it should cover the full width of the entrance. The depth may vary from 3 - 4 courses of setts or paviors to several meters depending on the design and layout of the driveway entrance.

    Commercial Edgings
    Where Nidagravel gravel grids are installed in any commercial or public setting it is important to install a suitable and robust edging.
    Yes, you can. Nidagravel gravel grids are ideal for gravel patios, terraces, and seating areas. Nidagravel grids create a nice stable gravel surface that provides a firm base for garden benches, tables, and chairs. The firm, stable surface is also much easier to walk on and wheel items across, such as wheelbarrows and BBQ's, etc. Depending on the size of your gravel patio you can either use Nidagravel 129, which is our small format gravel grid. Each sheet of Nidagravel 129 covers 0.96 sqm and each sheet is 1.2m x 0.8m and 30mm thick. It's ideal for small areas. Or you can use Nidagravel 130, which is a larger sized gravel grid, which covers 2.4 sqm per sheet and is, therefore, quicker to lay. Both Nidagravel 129 and Nidagravel 130 gravel grids are 30mm thick and compatible with each other, so you can both types of gravel grid in the same area.
    No, you will not see the honeycomb gravel grids at all once installed and filled with gravel. Nidagravel 129, 130 and 140 gravel stabilisation grids are specifically to stabilise gravel. They are also designed to be lightweight with a high compressive strength and invisible when installed. When you have installed and cut your Nidagravel grids to fit, you are ready to fill them with gravel. When filling our grids with gravel you fill them to the top of the grid and then overfill them by 20 - 25mm. This overfill layer allows for natural settlement and compaction, which will happen after the gravel grids are filled, as the gravel settles down into the individual cells. The surface covering of gravel also hides the grids from view, so all you will see is a lovely, flat gravel surface.

    Using Nidagravel grids will ensure your gravel surface remains stable, prevents potholes and ruts from developing and makes walking, driving and using the surface generally much easier.
    Yes, you can use Nidagravel gravel grids on a sloping driveway. In fact, Nidagravel grids are ideal for sloping gravel driveways as they stabilize the gravel surface and help prevent any gravel migration and loss of gravel. Our gravel stabilisation grids work by holding the gravel within honeycomb cells, which prevents the gravel from moving. A surface layer of gravel is laid on top and this interlocks with the gravel that is held within the cells. This results in a very stable surface with minimal movement of gravel. The Nidagravel system is also completely permeable and designed to be invisible.

    Nidagravel gravel grids can be used on sloping gravel driveways of any gradient up to 15%. The maximum slope gradient of 15% equates to 8.53 degrees or a ratio of 1:6.67. In simple terms, if describing the maximum gradient as a fall, it would be a fall of approx 15cm per metre. On slopes of up to 15%, the Nidagravel system will perform effectively with very low gravel migration. Whilst Nidagravel could be laid on steeper gradients, we do not recommend this as it may lead to greater movement of the surface layer of gravel over time.

    You can find further information about laying Nidagravel grids on a sloping driveway by clicking on the link below. We also have a Gradient Calculator to help customer calculate the gradient of their driveway
    Gradient Calculator

    For sloping driveways that have a gradient close to 15% we recommend using Nidagravel 140, as this is our highest specification gravel grid and most suited to steeper gradients up to a maximum slope gradient of 15%. Nidagravel 140 gravel grids are 2m x 1.2m in size, 40mm thick and each sheet covers 2.4sqm. If the slope gradient is between 10 - 15% we recommend using Nidgravel 140, our most robust grid, which holds a greater quantity of gravel making it ideal for containing gravel on a slope.
    Yes. The Nidagravel gravel stabilisation grid system is fully SuDS compliant. Nidagravel gravel grids form a porous surface that is 100% water permeable. The full surface area of a Nidagravel installation is permeable, which is a much greater permeable surface area when compared with permeable block paving systems. Where are permeable and natural surface finish is required, Nidagravel gravel grids are an ideal solution.
    Nidagravel grids are made from plastic, to be specific they are manufactured from polypropylene. It is fair to say that plastic products are not considered environmentally friendly. But as the manufacture of plastic products go, Nidagravel is actually pretty environmentally friendly. Here are some Eco Facts about Nidagravel gravel grids:

  • Nidagravel is made using 30 - 50% recycled materials.
  • Nidagravel grids themselves can be recycled and are 100% recyclable.
  • Polypropylene is a chemically inert product and therefore does not cause pollution during the manufacturing process.
  • 100% of the water used to make each sheet of Nidagravel is recycled as part of the manufacturing process.
  • The light structure of Nidagravel grids means the use of energy for production is limited and far less than other manufacturing processes.

  • Transportation
  • The lightweight nature of Nidagravel means that transportation of the product uses much less fuel and energy. Especially when compared with alternative products such as block paving.
  • The transportation of Nidagravel is limited. Nidagravel grids are shipped direct to Nidagravel UK and then direct to the end-user for installation.

  • Environmental
  • Nidagravel is 100% permeable and meets all SuDS requirements.
  • Use of Nidagravel reduces surface runoff from driveways and helps to prevent flooding.
  • Use of Nidagravel grids helps maintain local groundwater levels by allowing water to percolate away into the ground
  • Use of Nidagravel grid surfaces reduces the risk of flash flooding by reducing the burden of rainwater run-off on stormwater systems
  • Nidagravel grids helps reduce weed growth in gravel surfaces and therefore require less herbicide use in its ongoing maintenance.
  • Nidagravel grids are not a disposable plastic item, like single-use packaging. Nidagravel systems can remain for in place for well in excess of 75 years.
  • You can order Nidagravel gravel stabilisation grids direct from Nidagravel UK via our website. We hold large quantities in stock at our warehouse in Northamptonshire and ship orders to customers all over the UK within 48 hours from placing an order. We do not have a chain of stockists, but many builders merchants supply our products to order for their customers. You can order from a large number of independent builders merchants, as well as national builders merchants including Travis Perkins, Buildbase, Jewsons and Keyline.
    You can use Nidagravel 129, 130 & 140 gravel stabilisation grids for your driveway. But there are a number of factors that will effect your choice, these are the size of your driveway, the gradient of your driveway and the size of gravel you wish to use.

    Size of Driveway
    For small driveways up to 50 sqm and parking spaces, you can use Nidagravel 129. This is our small format gravel grid and its ideally suited for smaller projects. For medium to large gravel driveways it makes sense to use either of our large format gravel grids, Nidagravel 130 or Nidagravel 140. These larger grids are much quick to install and for larger projects this speeds up the installation time and also results in less joints across the surface area of the driveway. Nidagravel grids can for all sizes of gravel driveway from a single parking space of 10 sqm up to large sweeping driveways in excess of 2000 sqm.

    Gradient of Driveway
    We recommend that the maximum slope gradient for a Nidagravel grid driveway is 15%. Whilst Nidagravel 129, 130 and 140 gravel grids can be used on slopes of up to 15% we recommend using Nidagravel 129 and Nidagravel 130 on slightly shallower slopes of up to 10% and to use Nidagravel 140 our highest specification and most robust grid on slopes from 10 - 15%. This will ensure optimal performance of your sloping gravel driveway. Please note that we also recommend using angular shaped gravel with our gravel grid range and this is particularly important when working with a sloping driveway as angular gravels will naturally interlock well due to their shape. When angular gravel is combined with Nidagravel grids, this is the best possible combination and results in a particularly stable gravel surface with very low gravel migration, which is exactly what you are trying to achieve when using gravel on a slope.

    Gravel Size
    We recommend a maximum gravel size of 10 - 12mm for Nidagravel 129 and Nidagravel 130 gravel stabilisation grids. This size of gravel can also be used with Nidagravel 140, but due to the deeper honeycomb cells of Nidagravel 140, this grid can also accommodate a 10 - 20mm gravel.

    Nidagravel 129
    Minimum size gravel 6mm
    Maximum size gravel 10 - 12mm

    Nidagravel 130
    Minimum size gravel 6mm
    Maximum size gravel 10 - 12mm

    Nidagravel 140
    Minimum size gravel 6mm
    Maximum size gravel 20mm

    So taking the above factors into account; if you have a small, level driveway and want to use a 10mm gravel - we would recommend Nidagravel 129 gravel grids. If, for example, you have a large driveway of say approx. 350 sqm in size with a gradient of less than 10% and you want to use an 8mm gravel - we would recommend Nidagravel 130 gravel grids. If you wanted to use a 20mm gravel for the same driveway - we would recommend Nidagravel 140 gravel grids. As a final example, if you have a sloping driveway with a gradient of 13% we would recommend Nidagravel 140 gravel grids.
    This depends on which Nidagravel gravel stabilistion grid you are using. You will require the following amounts of gravel to fill your Nidagravel sheets:

  • Nidagravel 129 Approx. 70 kg of gravel per sqm (Each grid covers 0.96 sqm and requires approx. 67kg of gravel to fill)

  • Nidagravel 130 Approx. 70 kg of gravel per sqm (Each grid covers 2.4 sqm and requires approx. 168 kg of gravel to fill)

  • Nidagravel 140 Approx. 80 kg of gravel per sqm (Each grid covers 2.4 sqm and requires approx. 192 kg of gravel to fill)

  • When filling your Nidagravel honeycomb gravel grids you should fill the grids to the top with gravel and then overfill the grids by approx. 20 - 25mm. The gravel overfill allows for some natural settlement and compaction of the gravel as it settles into the honeycomb cells after installation. After any initial settlement, there should be a layer of gravel approx. 15mm thick on top of your gravel grids. The above gravel calculations take into account overfilling the grids. This surface layer of gravel hides the grids, so all you will see if nice, flat and level gravel surface. We recommend that the surface is inspected visually, 2 - 3 weeks after installation. If any areas have overly compacted and the Nidagravel grids are visible, simply top up with more gravel. Also, if there are any high spots / areas of deep gravel on top of the grids, these should be raked out accordingly. Once the gravel fill as settled in over the first 2 - 3 weeks after installation there should be no further movement.
    No, Nidagravel gravel stabilisation grids are fully UV resistant. The Nidagravel grids are also designed to be hidden under a thin layer of gravel and so are not directly exposed to sunlight when installed.
    For gravel driveways, we recommend using angular gravels, chippings or decorative aggregates as these naturally interlock well and when combined with Nidagravel grids create a particularly stable and hard wearing gravel driveway surface. In addition to this, we recommend choosing a naturally hard stone, which can take the weight of regular use by cars and other vehicles without crushing over time. Some examples of hard stone include flint, granite, and quartz-based decorative aggregates. Some softer gravels and chippings are prone to be gradually crushed over time when driven over regularly and are best avoided.

    Finally, we recommend that customers use a 10 - 12mm maximum size gravel with our Nidagravel 129 and Nidagravel 130 grids and a maximum size gravel of 20mm with our Nidagravel 140 grids. You can use smaller sized gravels with all our grids, but we would recommend that the smallest size gravel be approx. 6mm. There is a wide selection of decorative gravels available in the UK that can be used with the Nidagravel gravel grid system and these include gravels like Golden Flint Gravel, Staffordshire Pink Gravel, Black Basalt Chippings, Silver Granite Chippings and many more. There are also a wide range of gravel suppliers around the UK including local quarries, garden and landscaping centres and builders merchants.
    Working out the gradient of your gravel driveway is quite simple to do. In order to calculate the gradient, you will need to know the length of the sloping section of your gravel driveway. We call this measurement the RUN. This is an easy measurement to take, simply use a tape measure or measuring rod, and measure the distance from top to bottom and record your answer. The next measurement you need to take is the difference in height between the top and the bottom of the driveway. We call this measurement the RISE. Depending on how steep and how long your gravel driveway is, this can be a little bit tricky, but you need to know this measurement in order to calculate the gradient. There are a number of ways to obtain the RISE measurement as follows:

    1. Use a self-leveling rotational laser level with surveying staff and detector. This is a professional bit of kit which contractors will use on site for setting levels and simple surveying, but if you have access to this bit of equipment it's the quickest way to take an accurate measurement. The laser level sits on a tripod, levels itself, and then projects a laser dot or beam. The detector which attaches to the surveying staff reads the laser beam and emits a beep when it detects the beam. The surveying staff, which is usually telescopic and extends to 5m in height is marked from 1cm to 5m. So once set up, this system is very quick and very accurate.

    2. Use a basic laser spirit level mounted on a tripod and a tape measure. The principle is the same as using the professional kit above. The laser spirit level and tripod kit can be purchased from any well known DIY store and this is set up and used to project a level laser dot. The laser dot can be difficult to see in bright sunlight, so it is best to do this on a cloudy day or early evening. Take a piece of white A4 paper and waive this in front of the laser to help you locate the laser dot, then measure from the driveway surface to the dot to get your RISE measurement. You may find that this laser set up is not big enough to take the measurement between the top and bottom of the driveway in one go. If this is the case, you would take a series of measurements up the slope, by measuring and moving the laser tripod set up. Add the results together to get your total RISE measurement.

    3. Time to go old school and get the string line out. This is a two-man job (two-person job). When obtaining your RISE measurement this way you will need to hammer a stake or pin into the top of the driveway. Then attach the string line to the stake or pin and ensure that the string line is touching the surface of the driveway. Walk down to the bottom of the sloping driveway reeling out the string line as you go. At the bottom of the driveway attach a simple string line spirit level. A string line spirit level can be purchased from any well known DIY store. It's small, inexpensive, and fits in the palm of your hand. As the name suggests, it's basically a tiny spirit level with two clips to attach it to a string line. Pull the string line as taut as you can, without pulling the stake or pin out and without snapping the line. When the string is taut and level, ask your friend to measure the distance from the string line to the driveway surface. You now have your RISE measurement.

    With RUN and RISE measurements you can now calculate the gradient using a mathematical equation, or alternatively go to our Gradient Calculator, enter your measurements and this will calculate the gradient for you.
    Firstly, the depth of sub-base required for a Nidagravel gravel stabilisation grid driveway is no different to the depth of sub-base required for a driveway that is to have a block paved, tarmac or concrete surface finish. Whatever surfacing option you choose for your driveway, there will need to be a sub-base underneath. The sub-base is the foundation to the driveway surface and it needs to be of the correct depth and properly compacted. Getting depth and compaction right will mean the sub-base is strong enough for the intended loads to be imposed upon it and that it will not subside or move.

    The depth of a sub-base is not an exact science. It can depend on a number of things, which include ground conditions, soil types, height of the water table, weight of vehicles that are going to use the surface, the proximity of mature trees and maybe even the type of sub-base material used. We could get really technical here and start talking about the California Bearing Ratio (CBR) which is a test to evaluate the strength of the sub-grade (the sub-grade is the term for the ground underneath the proposed sub-base or in this case the footprint of the driveway). But we are not going to go too in depth with this aspect in answering this particular question. You may wish to do some research on the CBR if it is of particular interest to you.

    If we assume average ground conditions, average drainage, average soil type of sub-grade, etc - it is generally accepted as best practise by most contractors in the UK that a standard residential driveway should have minimum sub-base depth of 150mm or 6 inches. If you wish to install a deeper sub-base up to 250mm in depth that would also be entirely acceptable. It is also considered best practise to lay a geotextile membrane down over the sub-grade first, before you start adding your sub-base material. The geotextile membrane acts as a separating layer between sub-grade and the sub-base. It prevents the sub-base material from being ground into the sub-grade and when loaded with sub-base material it helps to stabilise the ground.

    All sub-bases should be properly compacted to ensure the base is well consolidated and will not compress when vehicle weights are applied to the finished surface. When installing a 150mm deep sub-base for a gravel driveway, in order to achieve maximum compaction the sub-base material can be laid in 2 x 75mm layers with the first layer being compacted before the second layer is applied and then compacted. It should also be noted that the sub-base should follow the profile of the driveway surface, should be of an even thickness and should have a tolerance of +/- 10mm. When installing Nidagravel gravel stabilisation grids it is important that the sub-base is properly prepared. Once the sub-base has been compacted the surface should be blinded off with a 10 - 15mm layer of sharp or grit sand and this should also be compacted. You are then ready to lay out your Nidagravel grids to complete the installation. Preparing your sub-base properly will ensure that the underside of the gravel grids are in full contact with the sub-base when laid and when filled with gravel, any loads imposed upon the Nidagravel surface will be transferred through the gravel and the grid to the sub-base below, which provides the foundation and strength for the surface layer above.
    Yes, Nidagravel surfaces are simple to maintain and a little regular maintenance will keep your Nidagravel gravel path, driveway or car park looking good for years to come.

    In the first 2 - 3 weeks after your Nidagravel surface is installed the gravel needs to settle and compact into the individual honeycomb cells. This will happen naturally and with use, especially if the Nidagravel surface is a driveway, as the weight of the vehicles using the driveway will compact the gravel. After this 2 - 3 week period we recommend that customers do a quick visual inspection of the gravel surface. If any sections of the Nidagravel grids are showing through, the gravel needs to be topped up to cover the grid by approx 20mm. Also, if you notice any high spots of gravel over the surface area that are 40mm or more deep, these areas need to be raked out a bit to reduce the depth of gravel down to 20mm. If is often a case of raking out the high spots of gravel an covering the low spots where the gravel has completely compacted and the grid has shown through. Once your Nidagravel surface has 'bedded in' and you have adjusted the gravel - the surface is fully stabilised and you will experience very low movement of the surface layer.

    It is worth mentioning here, that if your gravel overfill is too deep it will reduce the effectiveness of the Nidagravel gravel stabilisation system and if the gravel grids are not covered sufficiently with gravel this can lead to damage being caused to the gravel grids over time. If you follow the advice regards inspecting the surface shortly after installation as detailed above, this will ensure there are no problems with your Nidagravel driveway. It is also a quick and simple thing to do, so there is no excuse for not doing it!

    So, your Nidagravel gravel surface is installed, its settled in nicely and you have inspected it and adjusted the gravel accordingly. So what's next?

    Well, not a lot really! You can enjoy using the surface and you should immediately notice the difference the Nidagravel grids make. All we recommend is that you maintain your Nidagravel surface in the exactly the same way you would maintain your garden or any other outdoor space.

    We recommend the following maintenance of your Nidagravel stabilised gravel surface:

    1. Periodically inspect the surface and top up the surface gravel layer occasionally if required.
    2. Remove any debris and leaves that fall on to the surface. A leaf blower can be very useful for this.
    3. If the occasional weed appears remove by hand or treat with a suitable weed killer.

    The amount of time it takes to maintain your Nidagravel surface will of course depend on the area of Nidagravel grids installed and the proximity of trees, as it is trees in the main that drop the most amount of debris onto a surface throughout the year. If we use a 150 sqm residential driveway as an example - it is likely that over the course of a year, you would need to spend no more than 3 - 4 hours completing some pretty basic maintenance. The same type of maintenance you should complete for any outdoor surface.

    In fact, Nidagravel stabilised gravel surfaces are arguably lower maintenance than block paved and paved surfaces. With block paving, you will often find that overtime moss will grow and weeds will seed into the joints between the block paviors that are filled with kiln dried sand. If left unchecked this can become a real problem and certainly requires some maintenance to ensure the block paving continues to look good. Block paved surfaces will also need jet washing and the joints re-sanding from time to time. This is messy and time consuming maintenance job. Similarly, paving slabs will also need to be swept and periodically jet washed to keep them looking good. Mortar joints can also crumble overtime and it is likely that some re-pointing will be needed over the lifespan of the paved surface.

    When it comes to maintenance - Nidagravel fairs pretty well and can certainly be classed as a low maintenance surface.
    In simple terms, the sub-base is the foundation for the surfacing layer and it ultimately provides the load-bearing strength for the installation. Sub-bases are required for all types of paved or stabilised gravel surface, whether that's a simple path, a driveway or a car park. Sub-bases are usually made up of a granite or limestone aggregate which contains a range of sizes from large pieces of stone up to approx 40 - 50mm down to smaller particles, called fines. It is the combination of these sizes that enable the sub-base material to bind together and compact.